1. Field of the Invention
The invention relates to a pharmaceutical packing or filling device, which comprises an extended or elongated hollow plastic body having an axial length and a cylindrical portion extending over at least part of the axial length, which is provided with an interior silicone lubricant layer in this cylindrical portion and which is tightly closed by a stopper. It also relates to a method of making this pharmaceutical packing or filling device.
2. Prior Art
In the pharmaceutical packing device comprising the extended hollow plastic body an elastomeric closing member, e.g. a piston or a piston stopper, is inserted in its hollow interior space, and is slidable in the extended hollow plastic body, bearing flexibly on its interior wall. Typical examples include plastic syringe cylinders for pre-filled syringes, injector devices for cylindrical ampoules and capsules, and also piston burettes in analytical chemistry applications.
In order to overcome various problems typically a silicone lubricant layer is provided on the interior wall of the hollow plastic body.
According to U.S. Pat. No. 4,767,414 and European Patent EP 0 201 915 B1 silicone oil is applied to the surface of the interior wall. In the method described in these references the surface is activated with ionizing plasma to obtain good adherence and the silicone oil applied to it is similarly treated with ionizing plasma.
This process is comparatively inconvenient. Also the silicone oil is comparatively non-reactive, i.e. free silicone oil, which is exposed to the contents of the hollow plastic body in operation of the piston. The introduction of the silicone oil in the human body in the case of injectors should be reduced to a minimum for known reasons. U.S. Pat. No. 4,844,986 describes a process for providing a silicone lubricant layer to the interior wall of the hollow plastic body by means of plasma polymerization for preparation of a coating of polydimethylsiloxane.
Also this process requires activation of the plastic surface and a multistep application process.
European Patent Document EP 0 329 041 describes a process for coating the interior wall of a hollow plastic body with a polysiloxane, or polysilane or polysilazane by means of an ionizing plasma, whereby an adherent layer of this material is first produced and then a thin lubricant layer is applied over it.
Also this process requires activation of the plastic surface and comprises many steps.
The same is true of the process described in EP 0 302 625 B1, according to which the surface of the interior wall of the hollow plastic body is first treated with plasma in order to obtain a plasma treated polymer surface. Then a layer of a polysiloxane lubricant is applied to that surface without plasma treatment. The polysiloxane lubricant is provided with a suitable predetermined surface tension so that it will wet the plasma treated surface completely.
Finally U.S. Pat. No. 5,338,312 describes a coating for the interior wall of a hollow plastic body, on which two lubricant layers are applied over each other, namely a base layer of silicone oil with a higher viscosity applied on the interior wall by means of an adhesive layer and a surface layer of silicone oil with a lower viscosity. The silicone oils of the individual layers are preferably cross-linked by means of ionized plasma.
Similarly expensive process engineering is required to provide the lubricant layers in this last process. Among other things, the surface layer contains much free, i.e. non-reactive, silicone oil.